This invention relates to catalytic converters for a combustion engine, and more particularly, to a catalytic converter having a portion thereof integrated into the exhaust manifold.
Common exhaust systems for a combustion engine include a manifold connected to the combustion engine atone end and bolted to an exhaust pipe at the other end. The exhaust pipe extends a distance from the manifold and has a catalytic converter system bolted thereto. These catalytic converter systems include a ceramic substrate having a catalyst coated thereon and a metal housing surrounding the substrate. A support mat is placed between the ceramic substrate and the metal housing. Although the ceramic substrate expands and contracts relatively little during operation of the combustion engine, the metal housing expands and contracts greatly. The mat support expands and contracts with heat to keep the ceramic substrate held firmly in the converter housing.
As the catalytic converter is moved closer to the engine, the difference in thermal expansion between the housing and the ceramic substrate becomes exacerbated. Further, as the converter system is moved closer to the combustion engine, the converter system sees violent pressure pulsations. These violent pressure pulsations tend to erode and damage the mat support. This may result in damage to the ceramic substrate since the mat would no longer be able to keep the substrate in place or may cause it to become dislodged. Once dislodged, the substrate will be broken up into pieces due to vibrations and blown downstream.
The present invention provides advantages over the prior art.
The present invention includes a manifold catalytic converter. The catalytic converter is positioned immediately adjacent the manifold. The manifold and the converter end cone are cast from a single integral piece and are not bolted together. The manifold/converter end cone casting includes an end cone wall having a shoulder formed therein for engaging the front face of a catalytic converter substrate. A lip or ledge extends from the shoulder and surrounds the outer surface of the ceramic substrate immediately adjacent the front face of the substrate. This lip or ledge provides a pressure pulsation barrier so the mat will not erode. A housing for the ceramic substrate is provided and is spaced apart from the ceramic substrate. A resilient support material is provided between the ceramic substrate and the housing. A second end cone is connected to the housing.
These and other objects, features and advantages will be apparent from the following brief description of the drawings, detailed description and appended drawings and claims.